You could try reviving them, but after that you will probably end up with very high internal resistance, capacity loss, performance loss, and cells getting hot when charging.
I have a couple LG 4.35V cells that went under 1V, decided to not discard them and they kept working just fine, it’s been about a year now. But I only charge them up to 4.2V and use on low-drain lights. They have lost about 25% capacity.
So proceed at your own risk, general rule of thumb is to discard them but modern 18650s are pretty safe, it’s not like they will explode or melt if you try to charge them. Just monitor the temperature when charging.
If the pack was still warm, to me that means this didn’t happen over a period of weeks. Maybe a day.
How can a SRK discharge cells all the way to zero in such a short time. Isn’t there a threshold voltage at least for the LEDs to turn on? If it was the associated circuitry of the driver it would have taken much much longer and the pack would not have been still warm.
How are you measuring the voltage, with your charger, or a meter?
Try searching in this forum on how to “jump-start” a fully drained battery or charge it in charger that is capable of “reviving” a fully drained batteries.
However, only proceed if you know the risk.
I’ve always heard if the cells are run down flat, and you can re-charge them as quickly as possible, it is better for the cells than waiting around to charge them later… someone correct me if I’m wrong…
Is INR considered a ‘safe’ chemistry? I wonder what that means for this situation…
i left a srk on till a dim glow and the batteries were above 2.5v.
a protected 25r does not sound likely as that defeats their high rate feature.
but thats the only scenario that makes sense.they would bounce back once load removed not stay at zero.
If it was me I’d toss the cells. They aren’t that costly, the price of a meal, and I’d always have in the back of my mind the concern that they could have an internal short. Piece of mind is worth a few bucks to me.
Many new chargers have the capability to bring back protected batteries …
Or get a fully charged battery ( 18650 )
And connect + to + and neg to neg for like one second … You may need to do it a few times , but should trip the safety circuit back to life …
When I look this question up, I find different sources, but all basically saying the same thing — damage from overdischarge begins a degradation in the cell that, over time, can lead to an internal short. That’s why they’re recycled not thrown in the trash — because it takes time for the internal short to develop.
Here’s a test of batteries (multiple cells, various configurations) that did not take cells down to zero, but cut the discharge off early enough that cells were not damaged:
That’s the idea. Don’t over-discharge. If you did over-discharge a cell, don’t cycle it, as that’s how the damage gets done.
Hm. I wonder where he got that idea? I can’t find it by searching.
I’d guess he was exaggerating the cautions that have been published.
It’s a tactic: make up a straw man, knock it down, and declare teh win.
After re-reading several times, I realize that I phrased it wrong. The rep did not claim that batteries would explode but rather that the fear of explosion is all over the internet and that is not the case. Nothing more nothing less about that.
Can I recharge it anyway? - Sure! And it may even look and act perfectly fine.
So why must I throw away my precious, precious battery? - The battery manufacturers and real experts say internal damage happens. The battery is at risk of “venting with flame” or “rapidly disassembling” (exploding) at any random time it feels like it.
But I’m a Man! I can deal with a little battery venting, flames, explosion. In fact, I like fire and explosions! - Do you have a family? Children? Anyone you care about? Want them breathing hydrofluoric acid or a fire in the middle of the night? Be a man and throw the damn things out.
The risk may be low but it does happen and people can die and houses burned down. Not worth it for a few bucks since explosions have happened and a google search will reveal them. It may seem wasteful but the consequences of a li ion explosion will cause huge amounts of regret.
Sounds like good advice. I like explosions and flames as much as the next guy, but not in my home and certainly not in my backpack. These dead batteries are on their way to the recycler.
You know, I forgot to note that my post (at least the more confrontational parts) wasn’t directed at you MechEngVictor. More directed at the type of person that I’ve sometimes seen show up and comment in these type of threads. Who says it’s perfectly fine, advises others to charge the li-ions up and never give it a second thought.
No worries! Yours was the most concise version of the overall opinion which is what I was looking for. The truth is, I tried several jump-starting techniques and none worked. I also have an Opus BT-3400 with the discharge/refresh feature and it didn’t even detect them. But even if it had, I would never have felt comfortable using them anyway.
For what it’s worth, I’ve jump started many batteries in the past. I notice that 30% of the time they simply won’t hold a charge. 50% of the time the capacity is less than half, and the last 20% they seem totally fine. Haven’t had a battery ever do much more than leak under extreme discharging and charging conditions. Had to light an Ultrafire battery on literal fire before it went off like a firecracker. (Disclaimer: I don’t recommend doing any of this at home :P)
i would be careful with the light these were run down in.it may have a short.thats a possible explanation for this event.
is this an original srk or a more recent one?
originals had a buck converter or 3.
newer have simple fet switch and resistors.hard to get a serious short in these.buck converter can get a shorted fet and draw a bunch till the fet or inductor burns up.
time to autopsy the light.
